Resistance unit



April 18, 1933. c. L. LYON El AL 1,904,487

Q ANCE UNIT Filed May 1, 1929 Inventor: Clinton I... Lgon, CLaude A11 agger; b9 His Attor'heg Patented Apr. '18, 1933 UNITED. STATES PATENT OFFICE CLINTON L. LYON, OF SCOTIA, AND CLAUDE A. JAGGER, OF SCHENECTADY, NEW YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK RESISTANCE UNIT Application filed May 1, 1929. Serial No. 859,650.

cations, our invention is particularly useful in connection with resistance units of the tubular type, such as used in radio apparatus, wherein a resistance conductor is lc-wound upon a tubular insulating support and covered with a protective insulating coating, such as'vitreous enamel, which is fused at a comparatively high temperature. It has heretofore been customary in many instances to provide the resistance unit with ring or band-like terminal members spaced longitudinally of the tube, the resistance conductor being secured to the terminals and wound with the required number of turns between adjacent terminals. General- 1 the entire resistance'unit is covered with the protective insulating coating, such as a coating of vitreous enamel.

It will be understood that in applying this coating it is necessary to fuse or bake the enamel in an oven at a comparatively hightemperature. Heretofore it has been found that band or ring-like terminals would slip or turn about the cylindrical supduring the fusing operation .the bands expand to such an extent that they practically float upon the cylindrical support. By reason of the uneven. surface tension of the vitreous enamel or of the spring action of the coiled conductor. or by reason of both of these forces acting jointly, the floating .terminals would be displaced about the tubular support. As a result of this action, the terminals of the finished unit would be displaced and moreover, the conductor was very apt to be torn, particularly where 'a very fine high resistance conductor was used. Moreover, it has been found heretofore that when a large conductor was .used, the spring accompanying drawing in which port during this fusing operation. Thus,

action of the coiled conductor would turn the terminals about the tubular support articularly those located adjacent the end si of the unit. As a result, the conductor was no longer secured against the outer surface of the support and the terminals were permanently displaced.

In carrying our invention into effect in One form thereof, we provide each of the terminals with an inwardly projecting portion which will be received by a cooperating depression in the cylindrical su port. To accommodate conveniently a num ber of terminals and to provide for their ready adjustment lengthwise of the unit, we providethe support with a longitudinally extending recess for receiving the terminal projections. For a more complete understanding of our invention, reference should be had to the Fig. 1 is an-elevation of a resistance unit embodying our invention; and Fig. 2 is an end elevation of the resistance unit.

Referring to the drawing, we have shown our invention in one form in connection with aresistance unit of relatively high re sistance and low current carrying capacity provide a plurality of longitudinally spaced resistance sections 11a, 116, 110 and 11d. It

will be understood that the number of conductor turns in each sectionwill determine the amount of resistance in the section.

Preferably, the tubular-support 10 will be formed of a suitable ceramic compound such as porcelain. The resistance conductor 11 will be formed of a material suitable. to give the desired resistance characteristics. Thus, if a very high resistance is desired the conductor may be formed of a nickel-chromium-iron alloy havin an iron content of approximately 25% an a chromium content 0 approximately 11% If a lower resistance is desired, the conductor may be formed'of-a copper-nickel alloy having a copper content of approximatel 55%. If a still lower resistance is desired: a nickel-man- 100 each resistancesection.

ganese alloy having a 1 to 2% manganese content may be used. The resistance unit is provided with a plurality of terminals 12, a terminal being positioned adjacent each end of the unit and a terminal being prositioned between hus, it will be observed that each resistance section is provided with a pair of end terminals.

resistance conductor yat ri ht angles to the ring connection portion. ese outwardly projecting end portions may be secured together in any suitable manner. Thus, these ends may be spot welded. Preferably, the terminal rtion 126 .-will be suitably apertured so t at the external connections may be efiected conveniently.

- In order to preventthe terminals from].

turning -or'slipp' about the cylindrical support, I provide e ring-like rtion 12a of sac alwith an mwar y projecting portion 12c. In order to accommodate the inwardly projecting portions .12 of the terminals, the tubularsu'pport 10 is provided in its outer surface with a recess 13 extendmg long'itudinally'of the tube. This recess 13 will serve to receive the projecting portions 120 of the terminals so that the termi- -nals will be securely interlocked with the p um each terminal will be loclred'.

-with a number of recesses or tor may port. It will be observed therefore,

aigainst rotation upon the tubular support. twill be understood that the support is'provided with a recess 7 extending longitudinally throughout its length in order that the terminals may be readily adjusted longitudinally of the unit, and because the manufacturing process is facilitated. However, the tubular support 10 may be provided depressions, rovided for receiveachdepression being p ug 120 of one o the terminals.

in the ach terminal is also provided with aplurality of circurnferentially spaced conductor securin means such as projections or lugs 14. us, the conductor may be secured to spaced lugs as is to aliord the will be observed that by' reason of these circumferentially spaced lugs, the conducbe connected at any of a' plurality of points within the length of a single turn 'une 8, the op osite end any of the circumferentially' resistance of the conductor section. I

lengths leading to and from the securing means will be ld closely against the outer surface of the tubular support. Moreover, the conductor will be secured so that its entire length will be properly covered with' the insulating coating.

Thus for instance, the conductor length leadin from the resistance section 111) towar the right of the unit, as viewed in the figure, will be passed under the nearest lug 14a, thence upwardly and over the outer surface of the ring-like portion 12m in a diagonal direction to the upper edge of the lug 14b, thence downward y and under the lug "14b, thence upwardly and dia onally across the outer surface of the ring-1' e portion 12a to the up or edge of the lug 14a and thence under t is lu'g' and back across the rin -like Iportion 12a tothe u per edge of the ug 14 from which it willgic passed under the lug 14b to the next resistance section 110. Thus, the conductor willbe wound or wrapped about the juxtaposed lugs so as to form a reverse loop simulating a figplorfiions of this being sec betweent e lugs 14a and 14 respectively, and the outer surface of the tubular sup ort. It will be understood that the lugs wi 1 be spaced from the outer surface of the tubular support so that while permitting conductor to pass beneath them, the conductor will'be pressed closely against the tubular surface. It will be observed that by reason of this arrangement, the conductor lengths leading to and from the securing means will be forced into intimate contact with the outer surface of the tubular support and moreover, that the portion of the conductor length forming the loop will be secured in closed contact with the terminal member. It is desirable althou h not indis nsable'to solder the conductor engths whic cross the terminal member. Preferably, silver solder should be used. It will be understood that the solder by completely covering this portion of the conductor prevents oxidation of the conductor during. the enameling process and thereby insures good electrical contact between the conductor and the terminal.

The entire resistance unit is provided with the vitreous enamel coating. As has been pointed out, resistance units of this character were more or less objectionable because often-times the. terminal bands slipped or lation with said (p turned about the tubular support while the vitreous enamel was bein fired. By reason of this, the terminals 0? the finished unit were displaced and moreover, often-times the resistance conductor was broken.

It willjbe observed that we have securely locked our terminals 12 so that it is impossible for them to be rotated about the tubular support. Thus, by reason of the inwardly pro ecting portion 120 formed upon the ring-like portion of each terminal together with the recess 13 provided to receive these inwardly projecting portions, any rotation or turning of the terminals is prevented. Thus, there is no likelihood of the resistance conductor being torn during the enamel firing process and, moreover, in the finished resistance unit the terminals willbe secured in their proper positions upon the tubular support and the conductor will be rigidly secured throughout its entire length.

What We claim as new and desire to secure by Letters Patent of the United States, is

1. A resistance unit or the like comprising a substantially cylindrical support provided with a longitudinal recess and a terminal for said unit comprising a portion embracing said cylindrical support so that it is secured thereon and a portion projecting into said recess whereby the terminal is secured against rotation on said support but can be readily adjusted longitudinally thereof.

2. The method of making a resistance unit or the like which comprises forming a cylindrical support with a depression there in, winding on said support an electrical conductor, providing a cylindrical terminal for said support formed with a reentrant por tion to fit in said depression and placing said terminal on said support with its reentrant portion fitted in said depression, secur ng said conductor to said terminal, then covering said conductor and terminal with an insulating enamel and then heating said enamel to fuse it to said support while preventing movement of said terminal on said support.

3. The method of making a resistance unit or the like which comprises providing an electrically insulating cylindrical supporting member formed with a groove extending lengthwise thereof, providing ringlike terminals formed with a reentrant pro-' jecting portion to fit said recess, arranging said terminals on said support in spaced rerojecting portions fitted in said recess, win ing a resistance conductor on said support in the spaces between said terminals and securing intermediate portions of said conductor to said terminals, covering said conductor and terminals with a vitreous insulating enamel and then heating said enamel to fuse it on said support.

4. A resistance unit or the like comprising a tubular support provided with a recess in 5. A resistance unit or the like comprising a tubular electrically insulating support provided with a recess in its outer surface extending longitudinally thereof, a plurality of terminals spaced-i longitudinally of said support, each terminal being encircled about said tubular support and having a portion projecting'inwardly so as to be received by said recess whereby the terminal is secured against rotation but can be readily adjusted longitudinally of said support, and

an electrical conductor wound upon saidsupport and secured to said terminals.

6. A resistance unit or the like comprising a tubular electrically insulating supporting member provided with a recess in its outer surface extending longitudinally thereof, a plurality of terminal members spaced longitudinally of said tubular supporting member, each of said terminals being provided with a ring-like portion encircling said cylindrical support and having a portion projecting within said recess whereby each terminal is secured against rotation on said support but can be readily adjusted 1ongitudinally thereof and a resistance conductor wound upon said tubular supporting member so as to form a plurality of longitudinally spaced sections between said terminal members.

7 The method of making a resistance unit or the like which comprises forming a cylindrical support with a depression in its surface, providing a substantially cylindrical terminal with a reentrant portion arranged to fit in said depression, placing said terminal on said support with its reentrant portion fitted within said depression and then winding said conductor on said support and securing the conductor to said terminal.

.In Witness whereof, we have hereunto set our hands this 30th day of April, 1929.

CLINTON L. LYON. CLAUDE A. JAGGER. 

